Several prominent Dutch health websites are not careful enough with their visitors' privacy, according to consumers organization Consumentenbond. A number use cookies without permission and some use an un-encrypted connection, NU.nl reports.

The Consumentenbond looked at a sample of 20 websites and found that none of them conformed to the Netherlands cookie law, which states that certain types of cookies may only be placed if the user gives permission. By placing the so-called tracking cookies, advertisers and marketing companies could find out that users are looking for information on particular diseases.

Sites that don't obey the cookie law include those of Alzheimer's Nederland, the Hartstichting, the Longfonds and general health sites like Gezondheidsnet and Dokterdokter, according to the organization.

The Consumentenbond also found that six of the 20 tested sites don't use encrypted connections, making it easier for hackers and other malicious people to see which pages someone visited.